900 Sei Mk IV
PS road tester Jonathan Bentman has a grin the size of a Lincolnshire horizon. “Wow,” he says. Thanks, JB. Only 999 more words to go. But then, like a tickled Italian inline six, he warms up and there’s no stopping him: “I didn’t expect a great deal,” he says of a first go on the 900 Sei. “But it’s a definite wow. It starts on the button and although on tickover it sounds like...” ...he pauses, searching for the right description... “...like a bag of nails (and bolts and spanners), once you rev it everything smoothes out, and the exhaust note is just bliss.”
The Sei is a mechanically noisy motor; internals were actually made by Moto Guzzi, and assembled at Benelli’s Pesaro plant with Friday afternoon tolerances.the odd puff of smoke from the Sei’s trombone exhaust plumbing confirms it.
Jonathan parks the Sei up under the watchful eye of its owner. Gordon is a retired civil servant, and this is his sparkling, 1988-registered, 6500-mile Sei 900 Mk IV. But it’s not his first. “I had one before this one,” he says. “It was beautiful; red and white with zero miles; been stored for years.the chap I bought it from, Max at North Cornwall Motorcycle Centre, re-commissioned it, but said look, if it’s an investment you don’t want to be putting miles on it.and after a while I didn’t see the point in having a bike I didn’t want to ride – so when Max got this one in, which is a Mark IV from America, he asked if I wanted to swap it. So I did.and now this one gets ridden regularly.”
And quite right too. For a start, the Benelli deserves to be seen as well as heard; it looks glorious, with Us-only cream and black paint offset by gleaming chrome engine covers and a custom-built six-into-six exhaust system. “It’s pretty, but a bit oddlooking,” says PS test rider Jimmy Doherty. Great, thanks, I’ll pass your critique on to legendary Italian automotive design house, Carrozzeria Ghia, who styled it (Ghia was owned in the 1970s, as was Benelli itself, and Guzzi, by Argentine automotive industrialist Alejandro de Tomaso).
But we all agree the Sei’s silhouette is streamlined, lightweight and comparatively simple set against the bulk of the CBX1000 and Z1300.that’s partly because the 900 is evolved from a 750 – the first Sei was shown in 1973, and launched in 1975.The motor was a bold attempt by de Tomaso to upstage the Japanese multis laying waste to a complacent European bike industry, partly by copying them: the 750 was closely based on the Honda CB500/4 (even down to bore and stroke), with the obvious extension of an extra pair of cylinders.the single overhead cam, two-valve, 76bhp inline six proved expensive, complex and with fragile electronics and finish.and despite early admiration for its ambition, the 750 wasn’t obviously better than its competition. Even so, a few were raced at the TT in the 1970s, including by Joey Dunlop.
And also, as it happens, by Jonathan Bentman’s dad Graham, in the 10-lap 1976 Proddy TT. “I liked the 750 Sei,” he says. “It was well-balanced, went where you directed it, was stable, held a line and felt safe. But the TT wasn’t kind to it. 10 laps at full pelt was always going to be difficult.at the end of the eighth lap there was oil everywhere, the cases were smashed where we’d decked it, it could barely pull its own weight, it was making the worst noises. I nursed it to the finish, and when it stopped it wouldn’t run again; the big ends were shot.”
That isn’t a fate likely to befall Gordon’s bike. By 1979 the 750 was bored and stroked to 906cc – and, although 80bhp still wasn’t enough to trouble the CBX and Z13, the chassis improved with a disc brake instead of drum at the rear, and suspension refinement – which often took the form of bolting on whatever components were to hand at the factory; the Sei, like many Italian bikes of the 1970s, had more than an air of expedient parts-bin specials.
Either way, the MKI 900 Sei steadily evolved into the MKIV, incorporating a variety of updates, most obvious of which were cosmetics – adding a bikini fairing to the round-headlight Sei, then enlarging it and switching to a square light (we’re not sure where Gordon’s round light and nose-cone come from). But the basic engine design stayed the same throughout the Sei’s life – which although it stretched for 10 years, only saw around 1800 bikes built.
Before I go for a spin, I ask Gordon what to look out for. “You have to treat it with kid gloves,” he says. “You can’t go racing into a roundabout and expect it to stop on a sixpence; you have to nurture it in.”
The Sei’s riding position is odd – the thin, flat seat is almost level with the slim tank and low ’bars, and ’pegs are so far forward my left boot needs wedging under the flywheel cover, which also obscures the sidestand. But it’s not uncomfortable; once flight status is checked on the altimeter-style Veglia clocks and the rowdy inline six is running, first gear goes in like a dropped hammer and the Sei burbles happily away with a singing, bubbling chatter.
Then it splutters and dies because I forget to turn the fuel tap on.a few hundred yards later, I’ve forgotten to the turn the other one on too – the Sei has one on each side, across three carbs feeding six throttle bodies,
minimising width between the knees. But it rocks off at a vigorous pelt and instantly puts a smile on my face.
“It’s engaging, isn’t it?” says JB. “Lighter than I expected, and lithe; the chassis delivers plenty of feedback.after a few corners I was genuinely pushing it in, with a crisp blip on the downchange – carburation is excellent – then loading it up and powering away – but not too aggressively.”
Gordon has a pair of Avon Roadriders on his Sei, and they hold the tarmac well enough to expose braking limitations – Gordon is right, these Brembos aren’t their finest hour.the Sei bounds along, swaying on its Hagon shocks and Marzocchi forks with a period ‘hinged’ feel if you press hard.
“When you go past people, they must think, ‘What the hell was that?’” says Gordon. “Anyone behind must be counting the exhaust pipes and wondering what it is. So yes, you do do a bit of posing with it,” he smiles. “It comes with the territory.”
Those six megas look great. It rides low at the back though